The Mantle Forsaken
by BloodRavenFan
Summary: What if the Ancient Humans left a fail-safe to ensure that Humanity is able recover much more quickly (and free of Forerunner interference) once the Forerunners had been destroyed? AU and lots of OCs.
1. Chapter 1

Disclaimer: I do not own any characters, names, and any copyrighted material used in this work. This is a fanfic, period. Everything belongs to their respective owners. Comments and constructive criticism are all very much appreciated.

Chapter 1: Defiance

_Charum Hakkor, 109,000 BCE_

All that was left of Humanity's once great armada hung in orbit over their capital and the last of their worlds. Humanity's home world of Erde-Tyrene had been amongst the first to fall…and, if all the indications were correct, soon Charum Hakkor would fall as well. The Lord of Admirals knew this to be inevitable even as he looked out of the bridge view ports of his flagship super-carrier. But if Humanity would fall…then it would fall in a blaze of glory. Of that he was certain…and of one other fact as well.

He knew that foolish woman, Yprin Yprikushma, sought to warn the accursed Forerunners of the dangers of the Flood once Charum Hakkor had fallen. He knew such a quest would be utterly meaningless, given the arrogance of the Forerunners. It mattered not though; he had already made certain arrangements for the future. His musings were broken off as one of his warriors came up to him with a message.

"My lord…" began the man with a short bow. "…Science Mistress Tyrea and her team report their preparations have been completed. Lord Captain Rias also acknowledges his new orders as well. That is all."

"Very good, my friend…" Forthencho, the Lord of Admirals acknowledged with a nod as he returned to his musings.

Yes, Humanity would fall here at Charum Hakkor. And it would rise yet again on Erde-Tyrene, as it had done so many times in the past. He had made certain of that.

* * *

_Erde-Tyrene, 109,000 BCE_

Science Mistress Tyrea sighed as she prepared to seal the vault hidden beneath one of the craters on the moon of Humanity's homeworld of Erde-Tyrene. Even as the Forerunners had overrun the orbital defences of Charum Hakkor, the Didact having thrown everything the thrice-damned Forerunner Warrior-Servants had available against Humanity's armada, the Lord of Admirals had set into motion his contingency plan. Even as he and most of the remaining ships and soldiers retreated to join the last stand on the surface, Lord Captain Rias had taken several ships and all remaining defence platforms in a feigned, scorched-earth retreat along the Galactic Rim to draw the Forerunners' attention even as she and her team silently slipped through the enemy lines aboard a captured Forerunner stealth vessel and made their way back to Humanity's home world.

As expected, the home world lay empty and desolate, and more importantly, unguarded, the Forerunners so certain of their triumph that they had left the cradle of their enemies unwatched. Tyrea knew, as Forthencho had known as well, that the Forerunners would soon return, taking all that remained of Humanity back to their home world to take their '…proper place in the Mantle'. Tyrea found herself sneering at the thought of such hypocrisy…and elated at the same time. The Forerunners would not exterminate her kind, and even if they were reduced to a pre-industrial state, there still existed hope for the future. Therefore she and those who stood with her had sealed in this vault a database holding all of their history, information on their and the Forerunners' technology, as well as star maps of the galaxy; and last, she had placed an AI here as well, to watch over the species as it rebuilt, and to assist them in reclaiming their legacy when the time came.

"Goodbye…my daughter…" she whispered, tears pooling at the corners of her eyes as the vast doors of the Vault of Ages closed before her.

"Goodbye…mother…" the AI responded, its last communication to the outside world until the time came.

* * *

As expected, the Forerunners had returned what was left of the Human race to Erde-Tyrene in the aftermath of the fall of Charum Hakkor. Humanity was reduced from a great race wielding the power to create worlds to a primitive, hunter-gathering collection of species. And as predicted, the Flood had returned to the galaxy, and the Forerunners' self-assured belief in the inevitability and perpetuity of their victory and power allowed the Flood to consume the entire galaxy. Kuyou watched as the Librarian sought to atone for the Forerunners' past mistakes by moving the species from harm's way, and even going so far as to designate them as the 'Reclaimers'.

She acknowledged the nobility of such a quest, yet she could not allow the Forerunners to taint the legacy of the Human race. She had given up her physical form, even her own family, all for the sake of Humanity's future, and she would be damned if she failed in her task. She watched and waited as the Forerunners' cleansed the galaxy with their mightiest weapons of war, and returned the species they had saved to the home worlds. And once the remaining Forerunners had left to rot in self-imposed (and in her opinion, justly deserved) exile, she had made her move. While she had been forbidden from directly interfering with Humanity's reconstruction until they had re-acquired slip-space capability on their own, she was not forbidden from watching over her kind. And so she reached out with her faithful, mechanical servants, and purged the species of all the genetic instructions imposed on the Human race by the Librarian.

And once again, she watched in silence…she watched as the Human race drowned itself in blood…and paradoxically, find its way to peace and unity. She watched as they looked up from the blood and carnage of war, and reach out into space. And finally, she watched as they reopened the door to the stars. The time had come…

* * *

_The Moon, 2291_

"My God…it's real. It's actually real!" Dr Mitchells, one of the scientists on the investigatory team sent to investigate a hidden vault located beneath the moon's surface that had recently made contact with the UEG and the UNSC said. The message was clear: "_Humanity, the key to your destiny lies here._"

"But who could have made this vault? What did they put in it?" Major Sterling asked in bafflement; the massive doors before them were constructed of black metal that defied any and all attempts to scan them and what lay beyond.

"We'll know soon enough." Colonel Grant said in reply, as he stepped forward. As he did so, hidden scanners activated and began to scan the entire team, causing the soldiers present to draw their weapons in alarm.

"Wait!" Dr Janice shouted in alarm. "It's probably just making sure if we're Human or not. Or did you forget that the message was specifically addressed to Humanity?"

Before anyone else could reply, the vast doors opened. After a moment, the entire team entered the vault cautiously, looking around them in awe. Massive and ornate pillars of stone reached upwards from the floor to the vaulted ceiling, adorned with elegant and simple designs in red and gold. Between the pillars, holographic screens projected streams of data, which continued non-stop as they proceeded down the centre of the vault to the far end, where a hologram of the Earth and its solar system was projected in grand majesty. As they finally reached the far end of the vault, a hologram of a woman was projected before them.

She was a beautiful, Asian woman perhaps in her early thirties, her long brown hair hanging freely down her back, wearing robes of green and gold. In her hands she carried a long, slender staff of metal, while her forehead was adorned by a tattoo of a third eye flanked by stylized wings. "You have come at last. You come before me to claim your legacy…and you are most welcome to do so." She said to them, her voice thick with emotion.

"W-who are you? What legacy?" Colonel Grant asked.

"I am Kuyou, Keeper of the Vault of Ages. And the legacy I speak of is your legacy, passed down to you by your ancestors."

"Wait a minute, are you saying that this place was built by Humans?" Dr Mitchells asked in surprise.

"Of course; you are Humans, therefore, your ancestors are Human as well." Kuyou replied, deciding to keep the fact that she was once Human herself secret for now.

"But that's impossible! Unless…unless, the prehistoric Humans…" Dr Janice struggled to comprehend the situation. Nodding in understanding, Kuyou swung her staff in a long, slow, arc. "I know this is hard to understand…therefore, allow me to enlighten you to your past."

Holograms were projected across the vault, causing the team to look around them in wonder as images of Humanity's long-lost golden age were shown to them, even more so as they perceived not just one, but many Human sub-species playing their role in the forgotten times of an ancient era. "One hundred and fifty thousand years ago, the many peoples of Humanity took to the stars as one, expanding across the region of space known to this time and age as the Orion Arm."

"From their home world of Erde-Tyrene, known to this generation as Earth, they reached out. They discovered many wonders, uncovered dark secrets…and encountered the Forerunners." Kuyou continued her tale, while the team viewed with interest the alien races being shown before them. "Rejecting the hypocrisy of the Forerunners and their so-called 'Mantle of Responsibility', Humanity turned their sights to the worlds on the edge of the galaxy, bordering the darkness of the void beyond, building their capital at Charum Hakkor. For a long time Humanity stood as rivals to the Forerunners, until the Flood came."

The team watched in horror as the parasite overrun Humanity's worlds, perverting and consuming everything it touched, and forcing their ancestors to burn their own worlds to stop the advance of the Flood. "Humanity fought to save the galaxy, and at great cost, succeeded in doing so. But the cost was high, and the Forerunners were quick to take of advantage of Humanity's weakness. They deemed the necessities the Humans took to stop the Flood as crimes against their Mantle, and came down upon Humanity with no mercy. Erde-Tyrene was among the first worlds to fall, a great blow against Humanity's will."

The team's faces twisted in anger as they saw Forerunner warships darken the skies over Humanity's worlds, putting Humans to the sword, and burning their cities to the ground. "Yet, Humanity refused to surrender. They continued to defy the Forerunners for a thousand years, bleeding their fleets and armies white as they drove Humanity back across the Orion Arm and the Galactic Rim, to Charum Hakkor. There Humanity made its last stand, a fifty-three year siege that ended in complete victory for the Forerunners."

As Kuyou ended her tale, the team was silent. "But then…" began Major Sterling. "…if we lost…why are we here? How did you come to be here?"

"The Forerunners could not destroy us despite their anger; their Mantle forbade them from doing so. The last of our kind were devolved to a pre-industrial state and imprisoned on our home world. At least…that's what the Forerunners thought." Kuyou paused and smiled, tapping the bladed base of her staff against the ground. "Even as Charum Hakkor fell, the Lord of Admirals sent my mother and several others here, to prepare this vault for you. They knew the Flood would return, and the Forerunners would destroy it at terrible cost for themselves. Within this vault, you will find everything you need to reclaim the stars: our history, knowledge about our and the Forerunners' machines, maps of the stars. And I will assist you, for such is my task."

"Wait, you said 'we'. Were you…were you once…Human?" Dr Janice asked. Kuyou nodded. "I was once. I gave up my physical form, my own family, to undertake this great task to ensure the future."

"And your mother; what happened to her?" Major Sterling asked.

"I do not know." Kuyou answered, bowing her head sadly. "After she sealed the vault, she sought to re-join Lord Captain Rias and his fleet. Their fate is not known to me."

"This Flood…the Forerunners…are they still around?" Colonel Grant asked, his eyes narrowing.

"Unlikely; the Forerunners unleashed a powerful weapon that wiped out the Flood and all sapient life at the end of their war with the parasite a hundred thousand years ago. All of you are descendants of those they 'indexed' for salvation. And even then, they imprinted our race with genetic instructions to control our development. Fear not…I have since removed the imprint. The Forerunners have gone into exile outside of our galaxy…I hacked their computers before they left this system." She raised a hand to forestall the next question. "Much of Humanity's advanced technology is based on reverse-engineered Forerunner technology. Enough so that they not only failed to detect my intrusion, but my existence as well."

The entire team looked to Colonel Grant as he crossed his arms and closed his eyes in thought. Finally, he looked up and said "One last question: how do you know we're not Forerunners? And assuming we are, what would you do about it?"

Kuyou narrowed her eyes before answering "Our technology is not that primitive…or did you forget that we fought the Forerunners for a thousand years and made them pay for the lives of our people for a thousand years? As for your second question, a fail-safe is built into the vault to destroy it in case of discovery by those damned fools."

Kuyou and Colonel Grant locked eyes…and after a moment, he sighed resignedly and said "Alright, you've won me over. I don't know how, but I promise you, somehow, someway, I'll convince UNSC HIGHCOM of your story and the value of what you possess."

Kuyou smiled wearily, and said "Then I hope for all our sakes, they do."

"Well, I suppose we can just hope for the best, I suppose." Dr Mitchells said, looking at Dr Janice, who nodded and looked at Kuyou before saying "I look forward to working with you, Lady Kuyou."

* * *

2291: After long deliberation, UNSC HIGHCOM and the UEG leadership decide to publicize the existence and history of the ancient Human civilization. Even as religious groups across Earth and its solar system are thrown into turmoil as a result of this revelation, scientists including Tobias Shaw and Wallace Fujikawa struggle to decipher all the information kept within the Vault of Ages alongside the Kuyou AI. The Kuyou AI is also publicly honoured as a hero for her great sacrifice to watch over Humanity's redevelopment.

2301: An improved variant of the Shaw-Fujikawa Trans-light Drive capable of traversing approximately nine hundred light-years in one standard day is put into production. The UNSC also launches Armament Program 2301, developing and fielding the first Human warships armed with advanced energy weaponry. Energy shielding for both military and civilian ships rapidly become commonplace, and as Humanity begins the first wave of extra-solar colonization, - focusing on settling/terraforming worlds within one hundred light years of Earth's solar system – the UEG and the UNSC are reorganized into the Earth Federation.

2341: The first wave of colonization ends with Humanity entrenched across an estimated two hundred worlds. The Federation concentrates on internal development, while improvements involving energy manipulation allow for the development of a new generation of energy weapons and shielding. Budgetary concerns delay their implementation for the Federation Space Forces, however, energy weapons and shielding finally become commonplace for the Federation Army, and while significantly less common, among the civilian population as well.

2381: The second wave of colonization begins, with the goal of settling/terraforming worlds up to a thousand light-years away from Earth. The EFF launches Armament Program 2381, introducing a new generation of ships, weapons, armour, vehicles, and equipment. The semi-autonomous Task Force: Titan is also founded to oversee non-orthodox operations the EFF cannot handle on their own.

2396: The second wave of colonization ends prematurely when the Insurrection is triggered by extremists who condemn perceived injustices by the Earth Federation to the Outer Colonies and their inhabitants. The EFF mobilizes to quell violence across the Outer Colonies, and to protect Earth and Inner Colonies.

2398: Heavy losses and minimal success in suppressing the rebels in the Outer Colonies forces the EFF to overhaul all its strategic and tactical doctrines, as well as its training procedures.

2399: The EFF launches a fresh offensive against the rebels. New tactics and strategies turn the tide in favour of the EFF.

2405: The Insurrection ends. Humanity is firmly entrenched across an estimated two hundred worlds (the so-called core worlds) and settled across another estimated four hundred worlds.

2411: Citing security concerns, the EFF convinces the Federation Assembly to fund Armament Program 2411, expanding the size of the military for improved security and control over the Outer Colonies. Increased tensions and a second rebellion are successfully prevented thanks to pre-emptive covert operations by the Titans.

2431: A memorial ceremony is held at Charum Hakkor, and is broadcast live across Human space via a newly-completed quantum entanglement communications network. The Forerunner monuments at Sothra Hakkor are transported to Earth as victory trophies; despite accusations of 'desecration' made by certain groups, public opinion is favourable over the act, due to resentment over Forerunner crimes against Humanity in their war against the ancient Human civilization.

2433: The slip-space portal at Earth which leads to Installation 00 is opened. Humans arrive at Installation 00 and take control of the Halo Array. Any and all Flood specimens are destroyed. A weapons research facility is established at Installation 00 to conduct research on known species once kept at Installation 00. The Titans launch Project: Re-Genesis, in an attempt to understand and apply the base principles of Precursor Neural Physics.

2434: Shield World 'Onyx' is opened. The Huragok there are taken into protective custody, and together with the Kuyou AI, begin to actively reverse-engineer Forerunner technology.

2464: The secrets of hard-light and Forerunner stealth technology are unlocked. Limited application of said technologies proceeds accordingly. At the same time, Project Re-Genesis begins to bear fruit with its research on Precursor Neural Physics.

2525: First contact is made with the Covenant. The Covenant-Human War begins. The Covenant Fleet of Retribution attack Harvest but are unable to breach the EFSF lines over the planet and are overwhelmed by the defense fleet on station.


	2. Chapter 2

Disclaimer: I do not own any characters, names, and any copyrighted material used in this work. This is a fanfic, period. Everything belongs to their respective owners. Comments and constructive criticism are all very much appreciated.

Chapter 2: The First Battle of Harvest

Fleet Captain Martin Spenser sighed as he looked over the latest situation reports for the Harvest system. A week had passed since their…disastrous first contact with an alien civilization. While the initial confrontation had ended in victory for the EFF, neither Spenser nor his superiors were so foolish to think that a war could be averted by this point, especially without a common language to communicate with. As a result, six cruisers had been placed under his command and sent to Harvest to serve as a first response force against the impending alien invasion, and the Federation had ordered an evacuation. While the Federation had also ordered a media blackout over the situation and were steadfastly refusing to answer any questions from the carrion birds of the media, that was of little concern for Captain Spenser, as his attentions were focused on the evacuation and preparing his modest force for the upcoming battle.

"Is there something on your mind, captain?" his second, Lieutenant Commander John Drake asked, walking up to stand beside the captain's chair on the bridge.

"No, not really…" the captain replied. "…two-thirds of the civilians on Harvest have already been evacuated, and none of our patrols have reported anything unusual in the outer system. Who knows? Maybe we just might finish the evacuation before the enemy arrives."

As those words left the captain's mouth, an alarm began to sound across the bridge. "Captain…" the crewman manning the sensor station shouted in alarm. "…we have slip-space portals opening approximately four planetary diameters away from Harvest!"

Captain Spenser cursed himself for jinxing the situation. "Are they friendly?" he asked; despite the fact that any reinforcements would have contacted him well before they arrived via the QEC Network, he still hoped they had simply forgotten to do so. That hope was truly and brutally crushed by the crewman's reply.

"Negative; none of the approaching ships have IFFs we recognize, nor are they of any class we field."

"How many are there?" Lieutenant Commander Drake asked.

"Seven capital ships, eighteen escorts. One of the capitals, presumably the flagship, is approximately 5.3 kilometres long. Another two ships, both approximately 2 kilometres in length are leading the advance while the remaining four capitals are guarding the flanks of their advance. They measure approximately 1.8 kilometres in length." The crewman responded, his voice betraying panic kept under iron control.

"What about the escorts?" the captain asked.

"They've divided themselves into groups of six, and are advancing in wedge formations ahead of and screening the capitals. All escorts measure approximately 1.7 kilometres in length."

Captain Spenser smiled; all enemy ships were smaller than his cruisers, though bigger didn't necessarily mean better. "Signal Governor Haji; cancel the off-world evacuation, and get the civilians out of the city and into the wilderness." He ordered, hoping that doing so would reduce civilian casualties in case an enemy ship broke through. Standing up, he walked over to and looked over the tactical display in the middle of the bridge. "We'll make use of tactical plan C5. Signal the rest of the fleet, and move the Helios into firing positions. Give the same orders to Colonel Maxwell on the ground, and inform Earth of the situation."

* * *

Fleet Master Voro' Tuyokee watched worriedly as the six human warships assembled into a staggered line even as armoured gun-ports slid open, and energy turrets moved into firing position. "_This doesn't look good…_" he thought. "_…their ships are bigger than ours, and their technology is completely unlike anything we've seen before._"

"Signal all ships; breakthrough formation, and launch all fighters!" he ordered.

"Commander; the enemy is launching fighters as well!" an Unggoy manning a nearby station reported.

"Raise our shields! Standby on pulse laser and plasma turrets!" he shouted.

* * *

"Main cannons…fire!" Captain Spenser ordered. In response, the dorsal energy turrets on his ship fired at one of the CPV-class Heavy Destroyers which were quickly banking to bring their energy projectors to bear and powering up their plasma turrets; the other five ships did likewise, AI-assisted targeting and fire cooperation ensuring each Federation cruiser would target only one enemy ship each. And while the enemy warships had managed to raise their shields…it simply wasn't enough to block the power of no less than six high-energy particle beams striking each ship dead centre. With their first salvo, the EFSF had succeeded in halving the number of enemy escorts, which exploded into burning hulks and fragments spiralling out of orbit to burn up in Harvest's atmosphere.

Simultaneously, the Federation cruisers fired off a salvo of missiles; pulse lasers lanced out, destroying most of the missiles, but many broke through the laser umbrella, striking the unshielded Covenant warships. Two CCS-class battle-cruisers were disabled as a result, even as the two fleets now began trading fire in earnest, the Covenant warships spitting out a veritable firestorm of plasma rounds and bright-blue energy beams, while the Federation cruisers fired back with red energy beams and dissected the Covenant warships with ease. At the same time, fighters of both sides duelled, Covenant plasma lashing out with white fire against purple Human particle beams.

Several squadrons of fighters broke through and closed in on three CPV-class heavy destroyers firing off missile salvoes. The destroyers raised their shields…only for the missiles to phase through the shields and hit home, blowing the ships apart.

Fleet Master Voro' Tuyokee quickly realized that they had no chance of victory; none of the Covenant's weapons could breach the Humans' shields - whose configurations were eerily reminiscent of those used by Forerunner constructs - while the red Human energy beams were cutting his fleet to pieces with surgical precision. His fighters had a slightly more even fight, although the Human shields still retained their superior strength. "We cannot hold!" he shouted to be heard over the chaotic din of the command room. "Signal all ships, prepare to…"

The Fleet Master certainly intended to retreat and gather additional warships to press the attack, but he would never get the chance. Even as he began to issue the retreat order, a Helios defence satellite had reached its firing position. "Helios-3…" Captain Spenser said. "…target the enemy flagship and fire!"

In response, Helios-3 (which was little more than a space station-sized energy cannon) – charged and fired a massive, red energy beam that literally swallowed up the CAS-class assault carrier leading the Covenant fleet, completely vaporizing it. The beam also clipped an RCS-class cruiser, critically damaging it and causing it to explode in short order. With the loss of their flagship, the Covenant fleet fell apart. The surviving warships attempted to flee, only to be vaporized as other Helios Automated Defence Satellites came into play and opened fire, while others were torn apart by Captain Spenser's ships. The surviving Covenant fighters attempted to launch suicide runs to no avail, either being shot down by Federation point-defences or exploding harmlessly against the Humans' shields.

"Well, so much for that, I guess." Captain Spenser said, watching as the two disabled CCS-class battle cruisers initiated self-destruct rather than be boarded and captured. "One thing's for sure, the Federation's not going to take this lying down."

* * *

A/N

Mesopotamia-class Cruiser

Role: Mass-production multi-purpose line warship

Length: Approximately 6000 meters

Width: Approximately 3000 meters

Height: Approximately 1500 meters

Engine(s): Military-standard nuclear fusion plant-drive, manoeuvring engines

FTL Drive: Second-generation Astral Sails

Other Systems: Energy shielding rated to Forerunner/Ancient Human standards

Armour: Super-strong high-density alloy of unknown composition and thickness

Armament: Six high-energy energy cannons along the dorsal sections, rated to Forerunner/Ancient Human capital ship standards, multiple multi-purpose launchers armed with a variety of ordnance (offensive missiles possess the ability to phase through energy shielding), point-defence lasers

Complement: Variable

Affiliation: Earth Federation Space Forces

Helios-class Automated Defence Satellite

Role: Limited-production orbital defence weapon

Length: Approximately 15000 meters

Width: Approximately 7500 meters

Height: Approximately 3750 meters

Engine(s): Military-standard nuclear fusion plant-drive, manoeuvring engines

FTL Drive: None

Other Systems: Energy shielding rated to Forerunner/Ancient Human standards

Armour: Super-strong high-density alloy of unknown composition and thickness

Armament: One ultra-high-energy energy cannon based on Charum Hakkor's orbital defence energy towers, point-defence lasers

Complement: None

Affiliation: Earth Federation Space Forces


End file.
